1. Field of the Invention
The present invention relates to lens technology, and particularly, to a system for checking centration of surfaces of a lens by measuring tilt thereof.
2. Description of Related Art
Nowadays, image pick-up devices (e.g., digital still cameras and camcorders) with portability and good imaging quality are popular with consumers. To ensure the portability and good imaging quality, designers use aspheric lenses with two aspheric surfaces (an aspheric surface near an object side of the lens and an aspheric surface near an image side of the lens) in these image pick-up devices.
In manufacturing process of the above aspheric lenses, tilt, an important component of centration, of the surfaces of the aspheric lenses is measured for checking quality of the lens. However, special measuring apparatus and specially trained operator are needed to measure tilt, which is difficult to use in mass production of the lenses because of low efficiency and high cost.
What is needed, therefore, is to provided a an easy system for measuring tilt of a lens.